The effect of microwave heating on three vegetable oils having different lipid compositions was studied. Sunflower, soybean and peanut oils in comparison with oil admixture of soybean and peanut oil (1:1, w/w), were selected for this study. Each oil was heated for 2, 4, 6, 8, 10, 12, 15 and 18 minutes in microwave oven. Peroxide value, free acidity and colour absorbance (at 420 nm) were proportionally increasing with the increase of heating period. Colour absorption threw light on the formation of browning products arising from phospholipids during microwave heating. Total tocopherol contents were determined by preparative thin layer chromatography, whereas the fatty acid compositions and formed epoxy acid were analyzed by capillary gas liquid chromatography. The formed conjugated dienes and trienes were determined by UV spectrophotometry. It was found that the total tocopherols of the microwave heated oils, decreased depending on the type of the predominating tocopherols. Also a relation of peroxide formation, during microwave heating, with changes in total tocopherol composition was discussed. It was found that polyunsaturated fatty acids generally decreased by increasing the heating period. The results obtained from the heated oil admixture helped interpret the results obtained from other heated individual oils.

The objective of this work was to determine some beneficial and bioactive minor lipid components in wheat germ and grape seeds as a result of milling industry of wheat and pressing of grapes in wineries. Sterylglycosides (SG’s) were isolated and fractionate into free and acylated SG’s by TLC and were determine as their1-anthroylnitriles (1-AN) by HPLC. Moreover, 4-desmethylsterols were isolated, derivatized into their trimethyl silyl derivatives and analyzed by GLC. Tocopherols and tocotrienols were directly analyzed by HPLC. In addition, fatty acids composition by GLC was accomplished. The results were compared to three conventional edible oils, namely, corn, sunflower and cottonseed. It was found that the wheat germ oil (WGO) and grape seed oil (GSO) contained reasonable amounts of whole sterols. Sterylglycosides fraction (SG), which have not been evaluated, it was found that the two by-products contained high amounts of SG’s and they were rich in free and acylated campe/stigma SG as well as free and acylated β-sito SG. Total tocopherols and tocotrienols components were found in very high amounts in WGO (1300 ppm) and GSO (380 ppm). It is noteworthy to mention that GSO contained significant amounts of alpha- and gamma-tocotrienols which prevent cardiovascular diseases and contained reasonable amounts of alpha- and gamma-tocopherols. On the other side, it was found that WG and GS oils were enrich in linoleic acid (omega-6), while linolenic acid (omega-3) was present in higher quantity in WGO.

Eight lipid patterns of Silybum marianum (L.) Gaertn seed oil, not hitherto reported, (20%) have been elucidated in this laboratory using capillary GLC and HPLC as main tools of analysis. The oil is rich in linoleic acid (53.3%) and oleic acid (21.3%). Five major triacylglycerols containing linoleic acyls namely LLL, LLO, LLP, LOO and LOP were detected by HPLC using FID detector, these triacylglycerols are also predominating in both cottonseed and sunflower oils but in different proportions. The total tocopherols content (260 ppm) was determined directly in the oil by HPLC. It was found that the oil contains alpha -tocopherol as a major constituent (84.5%) resembling sunflower oil. The whole sterols pattern, as determined as their trimethylsilyl derivatives by GLC, includes campesterol, 5-stigmasterol, beta-sitosterol, 7-stigmasterol, avenasterol and spinasterol. The four sterols lipid clases of free and acylated sterols and sterylglycosides have been determined as their 9- and 1- anthroylnitrile derivatives by fluorescence and UV- HPLC respectively.

The present investigation aimed to study the impact of roasting on the chemical composition and biological activities of sweet and bitter lupin seed oils. Lupin oils were extracted using petroleum ether (40–60) with ultrasonic assisted method. Lupin Fatty acids, phytosterols, carotenoids, and total phenolic contents were determined. In addition, antioxidant, antimicrobial, and antifungal activities were evaluated. The results showed a ratio between 7.50% to 9.28% of oil content in lupin seed. Unroasted (bitter and sweet) lupin oil contained a high level of oleic acid ω9 (42.65 and 50.87%), followed by linoleic acid ω6 (37.3 and 34.48%) and linolenic acid ω3 (3.35 and 6.58%), respectively. Concerning phytosterols, unroasted (bitter and sweet lupin) seed oil reflected high values (442.59 and 406.18 mg/100 g oil, respectively). Bitter lupin oil contains a high amount of phenolics, although a lower antioxidant potency compared to sweet lupin oil. This phenomenon could be connected with the synergistic effect between phenolics and carotenoids higher in sweet lupin oil. The results reflected a more efficiently bitter lupin oil against anti-toxigenic fungi than sweet lupin oil. The roasting process recorded enhances the antimicrobial activity of bitter and sweet lupin seed oil, which is linked to the increment in bioactive components during the roasting process. These results concluded that lupin oil deems a novel functional ingredient and a valuable dietary fat source. Moreover, lupin oil seemed to have antifungal properties, which recommended its utilization as a carrier for active-antifungal compounds in food products.